1. Field
Embodiments relate to a red light emitting device, a method of fabricating a light emitting device, a light emitting device package, and a lighting system.
2. Background
A light emitting diode (LED) includes a P-N junction diode that converts electrical energy into light energy. The LED may be produced by combining dopants of semiconductor compounds from the periodic table. LEDs representing various colors, such as; e.g., blue, green, UV, and red LEDs may be made by adjusting compositional ratios of the semiconductor compounds. For example, a red LED may include an AlGaInP-based LED to convert electrical energy into light having a wavelength in a range of about 570 nm to about 630 nm. Wavelength variation may be determined depending on an intensity of bandgap energy of the LED, in which the intensity of the bandgap energy may be adjusted by adjusting a compositional ratio of Al and Ga, and the wavelength may be shortened as the compositional ratio of Al is increased.
Application of the AlGaInP-based red LED has grown to include, for example, a light source for high color rendering index (high CRI) or a light source for a vehicle, and competition for AlGaInP-based red LEDs in the market is increasing. Accordingly, ensuring high optical power (Po) and/or electrical reliability may become important. For example, according to the related art, as current is injected, doping elements of carriers may diffuse into an active area to lower a light speed, and operating voltage Vf may increase. When a temperature or current is increased due to the heat emitted from an LED chip, external quantum efficiency (EQE) may drop.